Fixes the following sparse warning:
fs/ext4/super.c:1672:45: warning: Using plain integer as NULL pointer
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
                 * Initialize args struct so we know whether arg was
                 * found; some options take optional arguments.
                 */
-               args[0].to = args[0].from = 0;
+               args[0].to = args[0].from = NULL;
                token = match_token(p, tokens, args);
                if (handle_mount_opt(sb, p, token, args, journal_devnum,
                                     journal_ioprio, is_remount) < 0)